The present invention relates to powered hand tools, and more particularly to a hand-operated turret drill for quickly changing between a pair of rotary tools such as a drill bit and screwdriver.
Most multi-operations that are done with a hand drill are done using two tools: for example, a masonry hand drill bit and a screwdriver. With conventional hand drills having a single chuck for holding a tool, one must continually change back and forth between the two tools while not dropping or losing the idle tool.
It is known in the art of motor-driven hand tools to provide a magazine carrying a plurality of different tools and means for selecting a desired tool by aligning the tool with a chuck axis, sliding or moving the tool into place, and tightening the chuck. If another tool occupies the chuck, the tool change operation necessarily includes the initial step of loosening the chuck and returning the prior tool to its location in the magazine. Although designs of this nature are useful for eliminating the problem of lost tools, they do not significantly decrease the time involved in changing between tools. See, for example, U.S. Pat. Nos. 1,022,711; 4,604,005; 4,928,381; 5,022,131; 5,065,498; and 5,893,685.
It is further known in the art to provide a hand drill with a turret having a plurality of chucks for holding different tools, whereby the turret is rotated about an axis offset in parallel relation to the drive axis of the drill to select a desired tool. However, in designs of this type, the individual tool-holding chucks of the turret, and the tool shanks themselves, are often of a specialized reduced design in order to keep the hand drill to a reasonably compact and useful size. Consequently, conventionally sized tool-gripping chucks, and conventionally sized tools held thereby, are not well accommodated by these designs. See, for example, GB 1,073,681 and U.S. Pat. No. 2,679,770.
A problem common to both the single-chuck xe2x80x9cmagazinexe2x80x9d designs and the multiple-chuck xe2x80x9cturretxe2x80x9d designs mentioned above is that the idle tools extend beyond the profile of a conventional hand drill, thereby compromising the compactness and utility of such drills.
Therefore, it is an object of the present invention to provide a hand turret drill with the utility to quickly change back and forth between two different tools without having to adjust a chuck each time.
It is another object of the present invention to provide a hand turret drill that accommodates tools of conventional size and shank design.
It is yet another object of the present invention to provide a hand turret drill with a turret that normally resides entirely within an end view projected silhouette of a conventional hand drill.
In furtherance of these and other objects, a turret hand drill formed in accordance with a preferred embodiment of the present invention comprises a drill housing enclosing a drill frame and drive means, and a two-chuck turret mounted on the drill frame near a forward portion of the drill for swiveling motion about a pivot axis between a pair of releasably locked index positions wherein a selected chuck is drivably connected to the drive means by a clutch mechanism. The pivot axis of the turret extends downwardly and forwardly from the forward portion of the drill housing at an angle displaced from the rotational tool drive axis of the drill, and a pair of chuck assemblies are arranged symmetrically about the turret pivot axis such that the respective rotational axes of the two chucks are coplanar with the turret pivot axis. Accordingly, when one of the chucks is positioned with its rotational axis aligned with the drill tool drive axis, swiveling the turret one-hundred eighty degrees about the turret pivot axis will switch the positions of the chucks to bring the rotational axis of the other chuck into alignment with the drill tool drive axis.
Each chuck assembly includes a chuck, a chuck shaft with a chuck half of the clutch, chuck shaft bearings, a bearing housing, and a clutch retraction spring. In one embodiment, the bearing housing is mounted in a bore in the turret and is biased by the clutch retraction spring so that the bearing housing and chuck shaft are forced to engage the chuck half of the clutch with a drive half of the clutch. This also locks the turret in place. Pulling on the chuck disengages the chuck half of the clutch from the drive half of the clutch so that the turret can be rotated about the pivot axis.